Condylocardin.] PELECYPODA. 911 



end much shorter, convex. Sculpture consisting of regular and close 

 concentric riblets, interspaces narrower than the riblets ; in cross- 

 section the riblets are angular, the surface slightly excavated. Colour 

 white. Hinge normal. 



Diameter Ant. -post., 1 mm. ; dorso-ventral. 1-1 mm. : thick- 

 ness, 0-5 mm. 



Type in the Mus. Hist. Nat., Paris. 



Hob. Stewart Island, in 35 fathoms, type (Filhol) ; Foveaux 

 Strait, in 15 fathoms (A. Hamilton) ; Bounty Islands, in 50 fathoms 

 (Captain Bollons). 



2. Condylocardia crassicosta, Bernard, 1897. Plate 53, figs. 6, a, b. 



Condylocardia crassicosta, Bernard, J. de Conch., xliv, 1896 (1897), 175. 

 pi. 6, f. 1 ; 187, f. 3 in text : May, P.R.S. Tas., 1908 (1909), pi. 6, f. 6. 



Shell minute, oblique, inequilateral, with a conspicuous prodisso- 

 conch, radially costate. Beaks contiguous, the prodissoconch with a 

 prominent exserted rim. Anterior end longer, margin descending, 

 lightly convex, narrowly rounded towards the convex basal margin, 

 which is ascending posteriorly ; posterior end short, the dorsal margin 

 straight, oblique, broadly angled on meeting the basal margin. Sculp- 

 ture consisting of 7 to 8 rounded and smooth radiate riblets, the inter- 

 stices subequal to the riblets. Colour white. Basal margins slightly 

 crenate within. Hinge normal. 



Diameter Ant. -post., 1-3 mm. ; dorso-ventral, 1-2 mm. : thick- 

 ness, 0-8 mm. 



Type in the Mus. Hist. Nat., Paris. 



Hab. Stewart Island, in 35 fathoms, type (Filhol) ; Foveaux 

 Strait, in 15 fathoms (A. Hamilton) ; Banks Peninsula (Iredale) ; 

 21| miles north-east of Wreck Reef, in 50-54 fathoms (E. R. Waite) : 

 Snares and Bounty Islands, in 50 fathoms (Captain Bollons). Also 

 Tasmania. 



Fam. LUCINID3C, d'Orbigny. 



Animal having a fairly thick mantle, adherent in some places to 

 the valves ; pallial muscle large, the anal orifice of the mantle some- 

 times produced into a siphon ; buccal orifice very small, the labial 

 palps reduced to tubercles ; gills large, thick, without an external 

 plate ; foot long, vermiform, distally swollen and pierced by a central 

 canal ; no byssiferous gland. 



Shell-substance porcellanous or chalky, usually with inconspicuous 

 epidermis, rounded, variably sculptured ; valves equal, free, closed, 

 with the beaks excavated in front ; adductor and pedal scars adjacent 

 or distinct, the latter small ; anterior adductor elongated, largely 

 within the pallial line, which is not sinuate ; area within the pallia! 

 line often granular or punctate ; cardinal area small, often deeply 

 impressed ; ligament and resilium subinternal, set in a deep groove, 

 but usually more or less visible externally ; hinge-plate distinct ; 



